Such optical fluid treatment device is known from the published patent document WO2012066440A1. More particularly, this document discloses an optical fluid treatment device comprising a fluid reservoir comprising a fluid compartment and a treatment compartment located at an upper part of the fluid reservoir. The treatment compartment houses a dielectric barrier discharge (DBD) lamp having a duct. A discharge opening of the fluid compartment adjoins an inlet opening of the duct, such that the duct is in fluid communication with the fluid compartment. When the fluid reservoir is handled by a user to pour fluid from it, the fluid reservoir will be tilted to cause fluid to flow from the fluid compartment through the duct to a jug discharge opening, and out of the fluid reservoir. When the fluid reservoir has been tilted, the DBD lamp is being activated to be operative, thereby generating light for treatment of fluid flowing in the duct. Such an optical fluid treatment device is being used for treatment of water.
The radiation is directed towards the inside of the duct having a relatively small diameter. Consequently, a relatively long duct is required to achieve minimum disinfection performance, thereby rendering the optical fluid treatment device less suitable for being used in relatively small fluid reservoirs. Another disadvantage of the known optical fluid treatment device is the difficulty for the end-user to visually detect fouling (such as inorganics, metals, bio-film etc) of the walls of the duct which necessitates expensive detection methods or may render the system unsafe after some time.